2) the only way to break the inevitable series of infinite regress is to postulate a "supernatural" cause

The problems with this little bit of logic are quite profound. Firstly, if everything that exists has a cause, than either the Supernatural cause is uncaused and therefor 1) is not correct or it does have a cause which raises the bigger question of what "caused" this supernatural cause.

Also, postulating a supernatural being with identity and capabilities is a complex structure, the whole idea of postulating "god" as a solution to the problem of complexity fails miserably unless this god is very simple indeed. (like a Deist god, which just pushed the "start" button and is not active in human affairs).

It isn't really a law. It's a necessary presupposition of understanding anything on the gross level. The subatomic level is understood in an entirely different way, though presumably there is some kind of cause and effect there as well. We use statistical ways of understanding the subatomic level due to some of the limitations on experimentation and observation there.

Getting back to the gross level where Newtonian and Einsteinian laws prevail, theists imagine that anything that runs according to laws must have a lawmaker. The advantage is that all of the causes and effects go back to a First Cause, which is an act of God.

However, that is a made up explanation. God must be proven first before using Him as a cause.